Facing Challenges of Reduction of Patient Radiation Dose ...uuid:3625118c-44f0-4e... · • Air cleanliness (postoperative infection prevention) • Thermal comfort for staff

DEVELOPING AND ADVANCING ENGINEERING KNOWLEDGE

FOR THE HOSPITALS OF THE FUTURE

International Federation Hospital Engineering of Europe

Italian Association of Hospital Architecture and Engineering

IFHE-EU 2017 European Conference for Hospital Engineering 2017 May, 29-31 Bologna (Italy)

Facing Challenges of Reduction of Patient Radiation Dose, Excellent Image Quality and Air Cleanliness in a Hybrid Cardiac Catheterization

Laboratory

Ludo VEREECKEN1*,MSc, Kim HAGSTRÖM2, DSc, Frédéric VAN HEUVERSWYN1, MD, Pascal DE WAEGEMAEKER1, MSc, Pekka KANERVA2, PhD, Ismo GRÖNVALL2, BSc, Sander RAMIOUL3, BSc

1Ghent University Hospital, Ghent, Belgium, 2Halton Oy, Helsinki, Finland (3Leuven, Belgium)






Challenges of patient safety in a hybrid OR• Reduction of patient and staff

radiation dose

• Excellent image quality

• Air cleanliness (postoperativeinfection prevention)

• Thermal comfort for staff(temperature and air velocity)

• Acoustic comfort (noise of ventilation systems)






Air cleanliness at rest and in operation conditions• Two basic requirements

• No infection due to pollution during the intervention

• No infection due to cross contamination

• At Rest conditions*

• General room cleanliness level ISO 5 (EN ISO 14644)

• Recovery Time (100:1) < 15 minutes

• In Operation conditions*

• < 10 CFU /m³ (CFU, colony forming unit – active sampling)

* CEN TC156 WG18, Hospital Ventilation Working Draft






Assumptions of LAF (golden standard)• Laminar Air flow

• Unidirectional low turbulence(Charnley’s principle*)

• No interference of the air currents

• Full side curtains

• Only protection under the LAF field

• Are these assumptions fulfilled in state-of-the art hybrid OR?

* Br J Surg.1964 Mar;51:202-5






Assumptions of LAF not fulfilled in hybrid OR






Halton Vita OR Space

Dilution principle, Controlled flow pattern

Putting

people

first

Ultraclean

operating

conditions

Flexible and

Efficient use

of space

Optimal

thermal

comfort

Silent

operational

environment

Ventilation

adjusts to

operating

needs






Nya Karolinska – Independent On-Site Validation

Conducted as a Simulated Operation (after At Rest qualification) at the finished Operation room with Halton Vita OR Space On-Site by Nya KarolinskaHospital and MyAir Qualification company without any involvement by Halton

Results:- Average 1,5 CFU/m3

- Maximum individual reading 4 CFU/m3

The full presentation may be downloaded from below link:http://www.r3nordic.org/_project/_private/userAssets/dfeb9598fbfb97cc6bbcc0aff2c785d6/myair_2016_nks.pdf






Materials and Methods TAVI

• Aortic valve stenosis = most common cardiac valve lesion

• TAVI = transcatheter aortic valve implantation

• Alternative for open surgical aortic valve replacement in selected patients with high operative risk






Materials and methods TAVI• Procedure requires optimal fluoroscopic image quality in a

perfectly sterile surgical environment

• Catheter is advanced over the wire from the femoral artery through the calcified aortic valve

• After balloon dilatation of the stenotic valve the new valve is placed inside the native valve

• Positioning of the valve requires rapid cardiac pacing to temporarily stop the pump function of the heart






Materials and methods• Computational Fluid

Dynamics Simulationusing ANSYS* CFD software

• Steady State analysis withSST turbulence model (shear stress transport)

• CFUs modeled as solidparticles injected from staffs face and feet areas

• Computational models had approximately 6 millionelements

* Ansys, Inc. Canonsburg, PA, USA






Comparison of LAF and Halton Vita OR Space• Green rectangle LAF 1,8 x

2,4 m

• Blue Ring: nozzles in Vita solution

• Critical zones – Red Areas

• Wound Area

• Instrument table 1 and 2

• The LAF corresponding tothe same air flow (about5000 m³/h)






Results LAF 1,8 x 2,4 m²• Field 1,8x2,4: no laminar flow in plane

2 (even under the LAF-field) due to C-arm

• Required surface to cover all critical zones = 4,2 x 5,6 m² � airflow 28.000 m³/h: notfeasible






Results LAF 1,8 x 2,4 m²• Microbial Cleanliness 0,9 m plane

• No control of flow outside of the LAF-field

• No uniformity






Results Halton Vita OR Space • Microbial Cleanliness 0,9 m plane

• Much more uniform conditions

• All critical zones are covered






Results Halton Vita OR Space • Microbial Cleanliness plane 1 OR table

• Good air quality next to the table, even under the C-arm






Results Halton Vita OR Space • Microbial Cleanliness critical areas

• Fulfills the requirements of < 10 CFU/m³






Results Halton Vita OR Space • Average recovery time by design 7 minutes (< 15 minutes)

• Age of Air illustration shows a good flushing of all critical areas(Plane 3 – Instrument tables)






Results Halton Vita OR Space • Thermal environment

• No direct draft of supply air to the operating staff (max 0,5 m/s)

• Air temperature more equalized due to dilution before entering the occupied zone ( 2 °C higher than supply air (Plane 2 – doctors))






Discussion• LAF and HAL give good air

quality in the wound area

• Only HAL gives good air qualityoutside the wound area

• HAL is less energy consumingthan LAF 3x3 m (50%)

• HAL gives better thermalenvironment due to dilution

(HAL – Halton Vita OR Space)






Further work • Building new cath lab

• Testing of airtight construction

• Commissioning of the system

• Validation of air cleanliness, radiation dose, image quality byan independent certified body






Conclusions • All challenges of patient safety must be examined when

designing and building a state-of-the art OR.

• Rethink the applicability of LAF in a hybrid cath lab (or modern OR) with large obstacles and need for clean conditions in different areas of the room. If Charnley’sprinciple is not fulfilled, CFD calculation is necessary

• The Halton Vita OR Space solution gives good air quality even in complex OR (ceiling-mounted devices, multiple critical zones)

• Staff comfort (thermal, acoustic by design) is optimizedin Halton Vita OR Space solution

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Facing Challenges of Reduction of Patient Radiation Dose ...uuid:3625118c-44f0-4e... · • Air cleanliness (postoperative infection prevention) • Thermal comfort for staff